particles fibres pulp whitepaper

7/25/2019 Particles Fibres Pulp Whitepaper

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WHITE PAPER

Minimizing damage

when processingparticles, fibresand pulp

A summary of challenges and solutions

Published April 9, 2015


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CONTENTS

Preventing particle, fibre and pulp damage via processing 3

Who is this white paper for? 3What elements are we dealing with? 3

Why does processing matter even more for beverages today? 4

Beverage processing challenges and solutions 5

Protecting particle integrity 5Product consistency 6Food safety 7Profitability 9

Summary 10

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Preventing particle, fibre and pulp damage

via processing

Who is this whi te paper for?

This white paper is for beverage plant managers who want to minimize product

damage when processing particles, fibres and pulp. It gives you practical

information and guidance on how to do so.

What elements are we dealing wi th?

Particleswithin beverage applications are typically 5-6 mm cubes, although there

is a trend towards even larger sizes. Particles have a wide range of properties; for

example, a Nata de coco particle which is fermented coconut water cut into cubes is quite rigid and strong while an Aloe Vera particle from the core of the plant

is very fragile.

Fibres are the destroyed sacs (i.e. pulp emptied of its juice) or other parts inside

the fruit. The mouth-feel of a product is dependent on the length of its fibres.

Pulp is the sacs, fruit cells or other parts inside a fruit that contains the fruits juice

(e.g., the pulp of a citrus fruit is the stringy content of the endocarp). When the

juice-filled sacs burst in the mouth, they deliver the mouth-feel of freshly squeezed

juice.

We sometimes refer to all three types as inclusions.

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Why does processing matter even more for beverages

today?

There is a global trend toward more and bigger particles in both beverage and

prepared food applications. The expanding market for beverages with particles, as

well as fibres and pulp, is putting new demands on processors and the technologies

they use to deliver high quality products. This is both because these constituents

are often fragile and easily damaged during processing and because there is an

endless array of combinations. Consequently, the lines between processing

categories are being blurred. Is it a beverage or a food when we put coconut in

juice or Aloe Vera in tea?

Beverage processors have traditionally worked with pulp and fibres, but particles

have become more important ingredients in the last 5-10 years. Consumers are

increasingly looking for enhanced, value-added, high-quality products with the

trend accelerating towards keeping natural fruit fibres in the beverages or mixing

particles or pulp into them to create products where consumers experience the

feeling of drinking fruit in liquid form. In other words, consumers are looking for

more than just a beverage. This trend is emerging from the fruit and food industry

where particles have been common for a very long time.

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Beverage processing challenges and solutions

A number of considerations have to be taken into account when processing

products with particles, fibres and pulp: How much damage to these inclusions is

acceptable? How do we measure this? Where in the process is the damage most

likely to occur and can something be done about it? How do variations, such as

ripeness or sugar content in the raw material, affect the process and the product?

How do the equipment factors e.g. the pumps, valves, heat exchangers

influence the final product?

Products containing particles, fibres and pulp need both specialized and customized

processing and packaging solutions. Each unique combination using these

inclusions poses processing challenges, and considerable risks in terms of productquality, food safety and profitability.

Protecting particle integrity

To achieve good product quality, particle integrity needs to be protected. This can

be challenging because all handling of raw material affects the product and because

particles, fibres and pulp are sensitive to mechanical shearing or tearing. Important

issues for pulp and particles are whether they come fresh, frozen or aseptic; their

properties (e.g. size and quality); and the preparation or mixing. A normal

acceptance level for reduction of particle content through processing within a

certain specification is 10-20% (note that this does not mean that all particles orfibres are lost or destroyed; they are reduced to the next specification).

Particles

Strength of a raw material may vary according to species, how it was ripened,

where and when it was harvested

Can be damaged via transport

Behave different than liquids

Fibres

Tend to be cut to pieces by centrifugal pumps

Pulp

Very sensitive to warming and mechanical stress

Difficult to deliver in a homogenous state so usually removed from fruit juice

by filtering it out

To ensure integrity, all three types of inclusion need to be pumped with minimal

mechanical treatment and without rapid pressure gradients. Special design and

dimensions are the basis for minimum maceration. Sudden pressure drops in

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control valves needs to be avoided, both from a maceration point of view but also

from physical dimensions, avoiding flow blockage.Positive pumpsof sufficient size with low slippage and limited speed are a good

bet for retaining product quality. Heat exchangersdesigned with fewer but larger

tubes of sufficient diameter and smooth inlets are also beneficial since larger

particles need larger tube diameters

Avoiding much maceration during processing also requires having control of raw

material quality and the ripening or softening of particles. This can be done in a

structured way and checked with instruments that measure particle characteristics

such as texture and strength. Measuring particle damage can also occur at various

processing stages so as to control the effects of the processing and fillingprocedures. This can be done via sieving and weighing, counting and measuring,

and sophisticated digital image analysisthat can measure the distribution of fibre

lengths and that can characterize particle shapes to provide valuable information on

particle distribution and size.

Processing beverages and other products that are naturally fibrous, or which

have fibres and particles added, inevitably damages them, explains Gran

Stjernberg, Line Solution Manager. Damage limitation is thus essential when

designing new systems or optimizing existing plants. Reviewing the entire process

to ensure particle integrity and fibre content is maintained can bring tangible

rewards.

Product consistency

However, the main challenge with all three from a product quality standpoint is the

floating or sedimentation tendency of the inclusions in the buffer tanks; if

formulation and recipe are not optimized for the density difference between

particles and carrier liquid, the particles will separate from the carrier liquid,

resulting in an uneven distribution in the consumer package. This affects the

consistency of the final product.

System design

To ensure product consistency, there needs to be proper internal design of the heat

exchangers such as the inlets of tube packages, tube sizes as well as tank and

agitators. Proper agitator optimization is of utmost importance to get an even end

product; the design of the tank dimensions and the agitator must match. Gentle,

low-shear agitation with slow, revolving paddle agitators gives a very good

agitation that is able to keep the particles in an even distribution through the

processing system without destroying the particles; good agitation doesnt

necessarily mean high shear mixing.

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Liquid over-processing

The liquid phase of a product should not be over-processed if high product qualityis to be achieved. Particles, fibres and pulp require longer heating time than the

liquid, which is sensitive to heat. This means that quality will be negatively

impacted when holding times are too long because of the presence of particles,

fibres and pulp.

To ensure that the liquid phase is not over-processed, solutions like dual stream

processing lines can be applied. Single stream processing linescan be used for

most liquid products, but can only handle smaller particle sizes, require a longer

holding time for the liquid phase, and make deaeration impossible. Dual stream

processing lines, on the other hand, employ separate product flows. They allow the

liquid to be processed in one line the conventional way for example, in a plate

heat exchanger or steam injection featuring standard pumps and processes while

the inclusions are processed according to their specific characteristics in another

line. The line also includes an aseptic blending of the two streams, juice and

inclusions. In addition to the prevention of liquid over-processing, the advantages

of using these are minimized mechanical treatment and higher particle integrity,

more efficient heating, and minimized thermal load on the end product. Splitting

the streams also allows for the liquid to be homogenized and deaerated to reduce its

free and dissolved air content, increase vitamin C retention, and minimize colour

change, aroma loss, and foaming in filler, so as to improve its quality. Particles

themselves cant be deaerated or homogenized.

An additional method is in-line dosing. This method adds the particles after the

homogenizer or deaerator, but before the final heat treatment in a single-stream

line. This way, the costly fruit content can be pasteurized gently and cost-

efficiently. Using aseptic in-line dosing of particles in a single aseptic processing

line, before aseptic filling, will yield better particle integrity. In addition, the liquid

can be homogenized and deaerated, and the optimal holding time for the liquid can

be used. This means a much smaller capital investment. However, particle size

limitation narrows the possible product range.

Food safety

The key heat treatment challenge when producing particulate beverages is to

achieve a safe product by ensuring that particles reach required temperature in the

coldest spot while simultaneously avoiding overcooking the liquid and surface of

the particle to preserve taste, colour, texture and nutrients. The other main

challenge from a food safety perspective is controlling for the formation of lumps.

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As shown in the graph, it takes time for the heat to penetrate into the centre of the

particle there is a temperature lag and the process needs to allow time for this.The heating time depends on the size of the particles. Optimizing heat treatment

requires selecting the right heat exchanger with an optimized heat exchanger

design, whether it is a coil formed mono-tube for larger particles or a multi-tube for

smaller particles; this requires an advanced multidimensional calculation that

determines heat transfer from the liquid into the inclusions. Selecting the right heat

exchangergives you control of retention time to ensure optimal heat treatment with

an optimized temperature curve. In a dual-stream process solution, heating is

tailored even further to ensure the optimal quality of liquid and optimal food safety

of particles.

It is also important to have an even distribution of particles throughout the system

so that they are heated evenly in the holding section. To achieve this, proper

mixing and agitation, and the density and viscosity of the liquid phase is important.

Running a pulp slurry with high particle concentration can be helpful to obtain

even distribution.

Heating of the centre of the particle is clearly delayed and

the centre does not reach sterilization temperature until it

reaches the end of the holding tube.

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Profitability

Beverages are particularly price-sensitive. To save on investment costs, it isparticularly important that the heat exchanger is properly dimensioned in order to

minimize energy use.

Another dimension of cost savings is the cost of raw materials. Because the chunks

and pieces are usually costly ingredients, minimizing damage to them and ensuring

preservation of their shape, consistency and flavour throughout transportation and

processing is very important.

But the overall cost driver for the line is product quality. Thus the process solutions

have to be balanced and optimized for product quality demands in a given context

of raw material cost. If raw materials can be obtained at lower cost, for example,then additional maceration or damage might be tolerated.

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Summary

There is a growing trend towards the inclusion of particles, fibres and pulp in

consumer products. Responding to this trend poses unique challenges for beverages

and prepared food manufacturers given that particles, fibres or pulp behave

differently according to their intrinsic properties and therefore require unique

processing solutions.

To ensure integrity, all three types of inclusion require special design and

dimensions of control valvesand pumps with low slippage and limited speed.

Heat exchangersdesigned with fewer but larger tubes of sufficient diameter and

smooth inlets are beneficial since larger particles need larger tube diameters.

Proper agitator optimizationis of utmost importance to get an even end product;

the design of the tank dimensions and the agitator must match.

Measuring particle characteristicssuch as texture and strength can occur at

various processing stages so as to control the effects of the processing and filling

procedures, and checking that particle distribution meets recipe requirements.

The liquid phase of a product should not be over-processed, which may occur when

particles, fibres and pulp require longer heating time than the liquid. Liquids with

larger inclusions may require dual stream processing lines, which allow the liquid

to be processed in one line the conventional way, while the inclusions areprocessed according to their specific characteristics in another line.

An additional method is in-line dosing, which adds particles after the

homogenizer, but before the final heat treatment in a single-stream line, allowing

costly fruit content to be pasteurized gently and cost-efficiently.

Careful calculations can lead to optimal processing, taking into account line design,

safety requirements, raw material costs, recipes and quality specifications.

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Tetra Pak your processing partner

Tetra Paks development engineers, process engineers, designers and field service

engineers work with you to create solutions for beverages and prepared foods with

particles, fibre and pulp.

At our Product Development Centresyou can experiment with recipes and use

the latest processing equipment for products that contain particles or inclusions.

You will have the full support of our food technologists and scientists.

We use an advanced multidimensional calculation tool that takes particle heating

time laginto consideration. This affects the choice and design of heat exchangers

when particles or inclusions are part of the recipe.

We also have extensive experience measuring product integrity using digital

image analysis, which shows how each processing step affects the character of

particular particles. This can help take the guesswork out of system design.

Feel free to contact your Tetra Pak representative or connect with us via our

website.

www.tetrapak.com/beverage-particles

For further details about processing inclusions, please contact:

[email protected], Line Solution Manager, or your local Tetra Pak

contact.

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